Flat Rock is a village in Crawford County, Illinois, United States.

Flat Rock was established in 1876 by John W. Jones, a merchant who would operate the first general store in the village.

Robinson, the Crawford County seat, is 10 miles (16 km) northwest of Flat Rock via IL 1 and Illinois State Route 33.

According to the 2010 census, Flat Rock has a total area of 0.86 square miles (2.23 km2), all land.

33.82% of all households were made up of individuals, and 11.27% had someone living alone who was 65 years of age or older.